JPH07143362A - Ghost eliminating device - Google Patents

Abstract

PURPOSE:To remarkably shorten the fetching time of an input signal, and to realize a real time operation of the ghost eliminating device. CONSTITUTION:An input signal (x) is supplied to a 1/2 line signal integrating part 19 in order to eliminate a noise, an area (1/2 horizontal line portion) in which equalizing pulses (ten pieces per a field) as reference signals exist is cumulated extending over several fields, and an equalizing pulse signal of good S/N is generated. Subsequently, as for the equalizing pulse signal, its rising part and falling part or the whole equalizing pulse are segmented by a reference signal segmenting part 131 in a reference signal generating part 13 and suppliedto a switching means 133. The switching means 133 outputs selectively one of signals from the reference signal segmenting part 131 or a typical waveform (the rising part, the falling part or the whole equalizingpulse) of the equalizing pulse stored in a reference signal ROM as a reference signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ghost eliminating device, and more particularly to a device for eliminating a ghost contained in an input signal of a television receiver or the like.

[0002]

2. Description of the Related Art When a radio wave transmitted directly from a transmission antenna of a broadcasting station and a radio wave reflected from a building or a mountain are simultaneously received by a reception antenna, images of both radio waves are respectively received. A so-called ghost failure occurs, which appears in a shifted manner.

In order to remove this ghost disturbance, a ghost removing device is used which processes an input signal with a filter circuit to remove the ghost signal. As the filter circuit, generally, a FIR type configuration as shown in FIG. 20 using a transversal filter, an IIR type configuration as shown in FIG. 21, or a configuration as shown in FIG. 22 using both of them is used.
The transversal filter in FIGS. 20, 21, and 22 is a circuit as shown in FIG. 23, and includes a plurality of delay devices for each fixed time, a plurality of storage devices for storing tap coefficients corresponding to respective taps, and tap outputs. And a tap coefficient, and an adder that adds the outputs from the multipliers. The tap coefficient is set corresponding to the delay time and the magnitude of the ghost.

The methods for calculating the tap coefficients of the transversal filter are roughly classified into a batch calculation method and a sequential correction method. Here, a widely used iterative correction method will be described.

It is assumed that the input signal is x _i , the output signal of the filter circuit is y _i , the reference signal is r _i , and the number of taps of the transversal filter is N. The error signal is defined as e _i in Equation (1).

[0006]

[Equation 1]

The square integral value E of the error signal e _i shown in equation (2) is used as the evaluation function representing the magnitude of the error.

[0008]

[Equation 2]

Generally, the iterative correction method is a method of repeating the correction of the tap coefficient so that the evaluation function E shown in the equation (2) becomes small. The correlation calculation result between the input signal x _i and the error signal e _i as in Equation (3) is defined as s _i,
When the value of the i-th tap coefficient c _i after being modified n times c _i ⁽ⁿ⁾ and α is a small coefficient, the modification of the tap coefficient is expressed as in equation (4), and c _i ^{(n) is changed} to c By updating to _i ^{(n + 1)} , the evaluation function E becomes gradually smaller.

[0010]

[Equation 3]

[0011]

[Equation 4]

Here, the coefficient α is empirically determined by the balance between the tap coefficient convergence and stability. When the coefficient α is small, the stability is good but the convergence is poor, and when the coefficient α is large, the convergence is fast but the stability is poor and the output diverges.

FIG. 24 is a block diagram of a ghost removing apparatus using the successive correction method. The ghost removing device receives the input signal x and outputs the output signal y as a filter circuit 6
1, an error signal generator 62 to which the output signal y from the filter circuit 61 is input, a reference signal generator 63 to generate a reference signal r supplied to the error signal generator 62, and an error signal generator 62. The correlation calculation unit 64 is supplied with the error signal e and the input signal x, and the tap coefficient calculation unit 66 is supplied with the signal from the correlation calculation unit 64.

In the above structure, first, the input signal x is input to the filter circuit 61 and the output signal y is output.
Next, the error signal generator 62 subtracts the reference signal r generated by the reference signal generator 63 from the output signal y of the filter circuit 61 to generate the error signal e. next,
The correlation calculation unit 64 performs the calculation represented by the equation (3) to obtain the correlation s between the input signal x and the error signal e. Next, the tap coefficient calculation unit 66 performs the calculation represented by the equation (4) to obtain the tap coefficient c. This is sent to the filter circuit 61 to correct the tap coefficient. The output signal y is calculated again, and the above correction process is repeated until the evaluation function E becomes small to some extent. By repeating the modification of the tap coefficient sufficiently many times, the final tap coefficient is obtained.

FIG. 25 shows a signal waveform in the above process, and an output signal y in which a ghost signal is removed from an input signal x is obtained.

Here, as the reference signal, the leading edge portion of the vertical synchronizing pulse in the vertical blanking period or the GCR signal inserted in the vertical blanking period is used. In particular, the GCR signal is a signal inserted for the purpose of removing ghosts, and its detection capability is very high. Further, the front edge portion of the vertical synchronizing pulse is a step signal, which is advantageous in that it is easy to handle.

[0017]

However, since the leading edge portion of the vertical sync pulse is only one in one field and the GCR signal is only 0.5 per field, the synchronization for increasing the S / N of the signal is required. There is a problem that a long time is required for addition. For example, the existing ghost removing apparatus requires a reference signal acquisition time of 1 second or longer.

Further, in the above-mentioned successive correction method, it is necessary to correct all tap coefficients including the position where the ghost does not exist as shown in the equation (4), and since the tap coefficients are gradually changed, the evaluation function is sufficient. Numerous correction processes are required before it becomes small. Further, as shown in Expression (3), it is necessary to perform N / 2 times of product-sum calculation processing on average in order to obtain one correlation value. Therefore, many operations are required,
It takes time to determine the tap coefficient.

Further, after the tap coefficient is corrected, the next correction is performed again based on the output from the filter circuit, so that the calculation in the filter circuit must be performed every time the tap coefficient is corrected. However, many calculations are required, and it takes time to determine the tap coefficient.

In stationary TVs, except for those caused by moving objects such as aircraft, there is almost no ghost fluctuation. Therefore, the above-mentioned problems regarding the signal acquisition time and the time required to determine the tap coefficient are not important. . However, in recent years, with the widespread use of vehicle-mounted or portable televisions, a ghost that fluctuates in a very fast cycle has become a problem, and a ghost removing device corresponding to the ghost is required. Specifically, human visual characteristics (afterimage effect)
Considering the above, a response of about 0.1 to 0.2 seconds is required.

Further, for all the tap coefficients of the transversal filter shown in FIG. 23, a tap coefficient memory, a multiplier and an adder are required, so that the circuit scale of the filter circuit becomes large.

The present invention has been made in view of the above problems, and a main object of the present invention is to provide a ghost eliminating device capable of faster response.

Further, according to the present invention, it is possible to shorten the acquisition time of the reference signal and detect the ghost faster.
Accordingly, it is an object of the present invention to provide a ghost removing device capable of faster response.

Further, according to the present invention, the tap coefficient can be obtained at a high speed by reducing the amount of calculation, and a faster response is possible, and at the same time, a memory, a multiplier and an adder of the tap coefficient constituting the filter circuit can be obtained. It is an object of the present invention to provide a ghost elimination device that can reduce the number of components and reduce the circuit scale.

[0025]

A ghost eliminating device according to a first aspect of the present invention is a ghost eliminating device which processes an input signal by a filter circuit and outputs a signal from which the ghost signal has been eliminated. Of the 12 equalized pulses in the line period, the correlation between the reference signal generating means for outputting 10 pulses other than the 1st and 7th pulses as the reference signal and the signal including the reference signal and the ghost signal is shown. Means to ask,
Means for correcting the tap coefficient of the filter circuit based on the correlation.

The ghost eliminating device according to the second aspect of the present invention is a ghost eliminating device that processes an input signal with a filter circuit and outputs a signal from which the ghost signal has been eliminated. Reference signal generating means for outputting a certain equalized pulse as a reference signal, means for obtaining a correlation between the reference signal and a signal including a ghost signal at the rising portion and the falling portion of the equalized pulse, and the filter based on the correlation. Means for modifying the tap coefficient of the circuit.

The ghost removing device according to the third aspect of the present invention is a ghost removing device that processes an input signal with a filter circuit and outputs a signal from which the ghost signal has been removed. A reference signal generating means for outputting a certain equalized pulse as a reference signal, a means for obtaining a correlation between the reference signal and a signal including a ghost signal for the entire equalized pulse, and a tap coefficient of the filter circuit based on the correlation. A ghost removing device comprising: a correcting means.

In the ghost removing device according to the fourth structure of the present invention, in the above-mentioned first to third structures, the reference signal generating means comprises a storage means for storing in advance a standard signal waveform of the equalization pulse. The reference signal generating means outputs a standard signal waveform of the equalization pulse stored in the storage means as a reference signal.

According to a fifth aspect of the present invention, there is provided the ghost elimination device according to any one of the first to third aspects, wherein the reference signal generating means comprises means for cutting out an equalized pulse from an input signal. Output a signal waveform cut out from the input signal as a reference signal.

The ghost eliminating device according to the sixth aspect of the present invention is a ghost eliminating device that processes an input signal with a filter circuit and outputs a signal from which the ghost signal has been eliminated. And a second signal including a ghost signal, and means for correcting the tap coefficient of the filter circuit corresponding to the position of the maximum value or the maximum value of the absolute value of the correlation. Is characterized by.

Further, in the ghost removing apparatus according to the seventh configuration of the present invention, in the sixth configuration, the means for correcting the tap coefficient uses the correlation as the correction value of the tap coefficient to obtain the correlation between the first signal and the second signal. It is characterized in that it is configured to use a value divided by a power integral value.

Further, the ghost eliminating device according to the eighth structure of the present invention is characterized in that, in the sixth structure, a reference signal is used as the first signal.

Further, the ghost removing apparatus according to the ninth structure of the present invention is, in the above-mentioned eighth structure, generating an intermediate signal by subtracting the reference signal from the input signal and correcting the tap coefficient for the intermediate signal. And further updating means, and the means for obtaining the correlation is configured to use the intermediate signal as the second signal.

Further, in the ghost removing apparatus according to the tenth structure of the present invention, in the ninth structure, the means for obtaining the correlation is provided between the rising portion of the pulse of the first signal and the second signal. Means for determining a first correlation, means for determining a second correlation between the trailing edge of the pulse of the first signal and the second signal, and the corresponding first and second corresponding correlations.
And a means for selecting a value having a smaller absolute value from the correlations to obtain a third correlation, wherein the means for modifying the tap coefficient is the maximum or maximum absolute value of the third correlation. The tap coefficient of the filter circuit corresponding to the position of is corrected.

Also, in the ghost removing apparatus according to the eleventh configuration of the present invention, in the ninth configuration, the means for obtaining the correlation is provided between the rising portion of the pulse of the first signal and the second signal. Means for determining a first correlation, means for determining a second correlation between the falling edge of the pulse of the first signal and the second signal, and the entire pulse of the first signal and the second signal And a means for obtaining a third correlation between the two correlations, and a means for selecting a value having a smaller absolute value from the corresponding first correlation, second correlation and third correlation to obtain the fourth correlation. The means for modifying the tap coefficient is configured to modify the tap coefficient of the filter circuit corresponding to the position of the maximum value or the maximum value of the absolute value of the fourth correlation. .

[0036]

According to the first structure, the reference signal generating means uses, out of the twelve equalized pulses within the vertical blanking period, ten pulses other than the first and seventh equalized pulses as reference signals. The correlation between the reference signal and the signal including the ghost signal is output, and the tap coefficient of the filter circuit is corrected based on this correlation. By using the equalization pulse as the reference signal, 10 signals can be used per field, so that the signal acquisition time can be significantly shortened, and therefore the ghost removal time can be shortened. .

According to the second configuration, the equalizing pulse within the vertical blanking period is output as the reference signal from the reference signal generating means, and the rising and falling portions of the equalizing pulse are compared with the reference signal. The correlation with the signal including the ghost signal is obtained, and the tap coefficient of the filter circuit is modified based on this correlation. By using the equalization pulse as the reference signal, 10 signals can be used per field, so that the signal acquisition time can be significantly shortened, and therefore the ghost removal time can be shortened. .

According to the third structure, the reference signal generating means outputs the equalization pulse within the vertical blanking period as the reference signal, and the entire equalization pulse includes the reference signal and the ghost signal. And the tap coefficient of the filter circuit is corrected based on this correlation. By using the equalization pulse as the reference signal, 10 signals can be used per field, so that the signal acquisition time can be significantly shortened, and therefore the ghost removal time can be shortened. .

According to the fourth structure, in addition to the operation of any of the first to third structures, the standard signal waveform of the equalization pulse stored in the storage means is output as the reference signal. . As a result, even a proximity ghost that overlaps the equalized pulse of the input signal can be removed.

According to the fifth configuration, in addition to the operation of any of the first to third configurations, the signal waveform cut out from the input signal is output as the reference signal. This makes it possible to eliminate the ghost even when the equalized pulse of the input signal deviates from its typical waveform.

According to the sixth configuration, the correlation between the first signal for comparison and the second signal including the ghost signal is obtained, and then the position of the maximum value or the maximum value of the absolute value of this correlation is obtained. The tap coefficient of the filter circuit corresponding to is corrected. The position where the tap coefficient is modified is limited to where the absolute value of the correlation has the maximum value or the maximum value, and only the tap coefficient corresponding to the position where the ghost exists is modified, so the evaluation function becomes sufficiently small. The number of corrections can be reduced. Therefore, the amount of calculation is greatly reduced,
The tap coefficient can be obtained at high speed. Further, since the tap coefficient only needs to be set at the position where the ghost exists, the number of tap coefficient memories, multipliers and adders can be significantly reduced, and the circuit scale can be significantly reduced. .

According to the seventh structure, in addition to the operation of the sixth structure, an appropriate value corresponding to the correlation is used as the correction value without using the minute coefficient α in the correction of the tap coefficient. The number of modifications can be reduced.

According to the eighth structure, in addition to the operation of the sixth structure, by using the reference signal r as the first signal for comparison, the area to be integrated in the calculation of the correlation is the reference signal. The tap amount can be obtained at high speed because the amount of calculation is reduced and the tap coefficient is limited to only the width.

According to the ninth structure, in addition to the operation of the eighth structure, the intermediate signal obtained by subtracting the reference signal from the input signal is used without using the output signal of the filter circuit as the second signal including the ghost signal. By using the signal and updating the intermediate signal in response to the correction of the tap coefficient, it is not necessary to perform the calculation in the filter circuit each time the correction of the tap coefficient is performed, the amount of calculation is reduced, and the speed is increased. The tap coefficient can be calculated.

According to the tenth structure, in addition to the operation of the ninth structure, the first correlation between the rising portion of the pulse of the first signal and the second signal, and the first correlation. A second correlation between the trailing edge of the pulse of the signal and the second signal is obtained, and a value having a smaller absolute value is selected from these correlations as the third correlation. Based on, the tap coefficient of the filter circuit is modified. Therefore, one of the two peaks in each of the first correlation and the second correlation can be canceled, and in the third correlation, a sub-peak does not occur and the peak becomes one. Further, the noise components included in the first correlation and the second correlation are canceled and
The noise component included in the correlation of becomes small. Moreover, since the correlation is obtained in the regions of the rising and falling portions of the pulse of the reference signal, the shape of the correlation peak becomes steep.

According to the eleventh structure, in addition to the operation of the ninth structure, the first correlation between the rising portion of the pulse of the first signal and the second signal, and the first correlation. A second correlation between the trailing edge of the pulse of the signal and the second signal;
A third correlation between the entire pulse of the first signal and the second signal is obtained, and a value having a smaller absolute value is selected from these correlations as a fourth correlation. The tap coefficient of the filter circuit is modified based on the correlation. As a result, the degree of canceling the noise component is further strengthened, and the noise component included in the fourth correlation is reduced.

[0047]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The ghost removing device of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

In this specification, obtaining the correlation means to shift one signal in time and obtain the correlation as a function of the shifted time, and the correlation means the similarity of two signals. Numerical value indicating the sex, the maximum value when the two match, and the minimum when the two are in the opposite shape, which indicates a negative value. In this specification, the correlation value is defined by the sum of products operation, but any function having the above-mentioned characteristics can be used in the same manner.

[Embodiment 1] First, FIG. 1 to FIG.
With reference to FIG. 3, a ghost elimination device capable of shortening the acquisition time of the reference signal and detecting a ghost at a higher speed, thereby enabling a faster response, will be described.

In this embodiment, an equalizing pulse within the vertical blanking period is used as the reference signal for detecting the ghost of the television signal, instead of the conventional vertical synchronizing signal or GCR signal. There are 12 equalization pulses in one field, but only 10 equalization pulses except the 1st and 7th can be used as reference signals. The first and seventh pulses cannot be used as reference signals because they have another signal immediately before them. Figure 2
This is shown in. The pulse indicated by the arrow in the figure is a pulse that can be used as a reference signal. Since 10 reference signals (pulses) can be taken in one vertical period, the signal acquisition time can be shortened. However, there is a problem that the amplitude is smaller (40 IRE) than the GCR signal (70 IRE), but since the number of signals per field is large, the signal integration time for noise reduction is about 1/7. Also, since the signal is not strictly defined, the ghost removal capability is poor,
Also, the ghost that can be handled is 0.5H (about 30 μsec)
Although there are restrictions such as the following, the use of the equalization pulse as the reference signal has sufficient value because the processing speed is given the highest priority and the long ghost is stochastically small.

The configuration and operation of the ghost removing device for removing the ghost by using the equalized pulse as a reference signal will be described below with reference to FIG.
It will be described in detail based on.

FIG. 1 is a block diagram showing the structure of a ghost removing device according to this embodiment. Ghost remover
A filter circuit 11 that receives an input signal x and outputs an output signal y, a ½ line signal integration section 20 to which an output signal y from the filter circuit 11 is input, and a ½ line signal integration section 20 Error signal generator 1 to which a signal is input
2, a reference signal generator 13 for generating a reference signal r supplied to the error signal generator 12, and a 1/2 line signal accumulator for generating a signal supplied with the input signal x and supplied to the reference signal generator 13. 19, a correlation calculation unit 14 to which the error signal e from the error signal generation unit 12 and the signal from the 1/2 line signal integration unit 19 are supplied, and a tap coefficient calculation unit to which the signal from the correlation calculation unit 14 is supplied It consists of 16. Here, both the 1/2 line signal integrating units 19 and 20 are inserted to remove noise of the input signal x and the output signal y, and equalized pulses (10 per field) are supplied from the supplied signals. ) Is accumulated over several fields to generate an equalized pulse signal with a good S / N.

The filter circuit 11 includes a delay line 111, a waveform equalizing transversal filter 112, and an adder 11.
3, 114, a delay line 115, and a normal ghost transversal filter 116. The waveform equalization transversal filter 112 is feedforward connected, and the normal ghost transversal filter 116 is feedback connected. The input signal x is delayed by the delay time of the previous ghost by the delay line 111 and then added to the ghost cancellation signal created by the waveform equalization transversal filter 112 to remove the previous ghost and perform waveform equalization. Be seen. Next, the normal ghost is removed by adding it to the ghost cancellation signal generated by the normal ghost transversal filter 116.

The reference signal generation unit 13 includes a reference signal cutout unit 131 for cutting out the equalization pulse from the signal from the 1/2 line signal integration unit 19, and a reference signal ROM 132 for storing a typical waveform of the equalization pulse in advance. , And a switching means 133 for selectively outputting either one of the signal from the reference signal cutout unit 131 and the signal from the reference signal ROM as a reference signal. Depending on the case, it may consist of only one of the reference signal cutout unit 131 and the reference signal ROM 132.

In the above structure, the input signal x is input to the filter circuit 11 and the output signal y is output. Also,
The input signal x is supplied to the ½ line signal integration section 19 to remove noise, and an area (1/2 horizontal line) in which there are equalized pulses (10 per field) to be used as a reference signal is several fields. To generate an equalized pulse signal having a good S / N. Then, the rising edge portion, the falling edge portion, or the entire equalization pulse of the equalization pulse signal is cut out by the reference signal cutout portion 131 in the reference signal generation portion 13 and supplied to the switching means 133. The switching unit 133 selectively selects either the signal from the reference signal cutout unit 131 or the typical waveform of the equalization pulse stored in the reference signal ROM (the rising portion, the falling portion, or the entire equalization pulse). Output as a reference signal.

On the other hand, the output signal y from the filter circuit 11
The same process is also performed in the 1/2 line signal integration section 20 to generate the equalized pulse portion of the output signal with improved S / N. Next, in the error signal generator 12,
The error signal is generated by subtracting the reference signal from the reference signal generation unit 13 from the output signal y ′ from the line signal integration unit 20. Next, the correlation calculator 14 obtains the correlation between the input signal and the error signal. Next, the tap coefficient calculator 16 sets an appropriate coefficient for the tap corresponding to the time when the ghost exists. This is sent to the filter circuit 11 to correct the tap coefficient. By repeating the above processing, the output signal y with few ghosts is output as the final output.
Is obtained.

At this time, as the signal range for calculating the correlation between the reference signal and the output signal, only the rising / falling portion of the equalizing pulse or the entire equalizing pulse is used. Depending on which one is used, the ghost removal performance is characterized (see simulation results described below), so it is desirable to use them properly according to the purpose and ghost situation.

Further, as the reference signal, a typical waveform of the equalizing pulse provided inside the ghost removing device is used, or a part corresponding to the equalizing pulse is cut out from the input signal to be used as the reference signal. , Take one. Even in this case, the ghost removal performance is characterized by which one is used (see the simulation result described later), so it is desirable to use them properly according to the purpose and the ghost situation.

3 to 7 show the results of ghost elimination simulation by the ghost elimination device. A reference signal including a ghost was generated, and a ghost removal simulation was performed on the reference signal. From the top, the figure shows the difference between the input signal (equalized pulse and its ghost), the output signal after ghost removal, the tap coefficient of the ghost removal filter, and the ideal output. Here, since noise of about 20 dB is superimposed on the input signal, a noise component remains in the difference from the ideal output and does not become zero.

FIG. 3 shows the result when there are three discrete ghosts. If the noise is small enough compared to the ghost to be removed, the ghost is almost completely removed.

FIG. 4 shows the simulation result when the reference signal (equalization pulse) deviates from its typical waveform.
And shown in FIG. When the reference signal is cut out from the input signal, the ghost is almost eliminated (Fig. 4).
However, when the reference signal is internally provided, when the deviation is large, not only the ghost cannot be removed but also a false ghost may be generated (FIG. 5). However, when the reference signal is cut out from the input signal, the reference signal may include noise or proximity ghost, and thus may be weak against them. It is necessary to analyze and select the actual conditions such as the deviation of the equalized pulse, noise, and proximity ghost.

A problem may occur when the reference signal is cut out from the input signal for a proximity ghost that overlaps with the reference signal (equalization pulse). At this time, the state of ghost removal in the case of using the entire signal of the equalized pulse as the reference signal and in the case of using only the changing part (rising / falling part) of the signal is shown in FIGS. 6 and 7. Shown in. When all the equalized pulse signals are used as the reference signal, since the proximity ghost is also captured as the reference signal, not only the proximity ghost cannot be removed but also the removal of other ghosts is adversely affected (Fig. 7). However, when the region to be calculated is only the rising / falling part of the equalization pulse, unless the rising / falling part of the proximity ghost overlaps this region (the probability of overlapping is expected to be relatively small). , There is no effect, and the ghost is neatly removed (Fig. 6). On the other hand, when the reference signal is provided inside, no problem arises in the ghost removal performance, and it is possible to sufficiently remove the near ghost.

As described in detail above, according to this embodiment,
By using the equalization pulse as the reference signal, the time required for capturing the reference signal can be shortened while maintaining sufficient ghost removal performance, and a faster response to the ghost becomes possible.

Next, the number of calculations can be reduced to obtain the tap coefficient at high speed, and a faster response is possible, and at the same time, the number of tap coefficient storages, multipliers and adders constituting the filter circuit can be reduced. A detailed description will be given of a ghost removing device that can be reduced in number to reduce the circuit scale.

Since the ghost to be detected is the one in which the reference signal appears with a delay, it can be understood from the characteristics of the correlation that the ghost has a maximum or maximum absolute value of the correlation. Therefore, by limiting the modification of the tap coefficient only to the point where the absolute value of the correlation has the maximum value or the maximum value, it is possible to obtain the tap coefficient at high speed by reducing the amount of calculation, and to reduce the circuit scale. Is possible.

Hereinafter, an embodiment of such a ghost removing device will be described in detail with reference to FIGS. 8 to 19.

[Embodiment 2] FIG. 8 is a block diagram of a ghost removing apparatus according to a second embodiment of the present invention. The ghost removing device is supplied with an input signal x and a filter circuit 21 that outputs an output signal y, an error signal generator 22 to which the output signal y from the filter circuit 21 is input, and the error signal generator 22. Reference signal generator 23 for generating a reference signal r, a correlation calculator 24 to which the error signal e from the error signal generator 22 and the input signal x are supplied, the correlation calculator 2
The maximum / maximum detection unit 25 to which the signal from the No. 4 is supplied, and the tap coefficient calculation unit 26 to which the output from the maximum / maximum detection unit 25 is input.

In the above structure, first, the input signal x is input to the filter circuit 21 and the output signal y is output.
Next, the error signal generator 22 subtracts the reference signal r generated by the reference signal generator 23 from the output signal y of the filter circuit 21 to generate the error signal e. next,
The correlation calculator 24 obtains the correlation s between the input signal x which is the first signal for comparison and the error signal e which is the second signal including the ghost signal. The correlation s is given by equation (5).

[0069]

[Equation 5]

Next, the maximum / maximum detecting section 25 detects the position where the absolute value of the correlation s has the maximum value or the maximum value,
The tap coefficient calculator 26 obtains the tap coefficient c corresponding to the detected position. The filter circuit 21 is IIR
In the case of the type configuration, when the tap coefficient c _i is set to a value obtained by removing the square integral value of the input signal x, which is the first signal for comparing the values of the correlation s as shown in Expression (6), The number of corrections of the tap coefficient c _i at the position is only once. When a FIR type filter circuit is used, it is dealt with by converting the tap coefficient.

[0071]

[Equation 6]

This is sent to the filter circuit 21 to correct the tap coefficient. The output signal y is calculated again, and the above correction process is repeated until the evaluation function E becomes small to some extent. The final tap coefficient is obtained by repeating the correction of the tap coefficient several times.

FIG. 9 shows a signal waveform in the above process, and an output signal y from which a ghost signal is removed from an input signal x is obtained.

As described above, the position where the tap coefficient is corrected is limited to the position where the absolute value of the correlation has the maximum value or the maximum value. Only the tap coefficient corresponding to the position where the ghost exists is corrected, and the small coefficient α Since the appropriate value corresponding to the correlation is used as the correction value without using, the number of corrections can be reduced.

The number of tap coefficients to be set is much smaller than the number N of tap coefficients set by the conventional iterative correction method. Therefore, a transversal filter using a variable delay device as shown in FIG. 10 can be used in place of the conventionally used transversal filter as shown in FIG. In FIG. 10, the number of tap coefficient storages, multipliers, and adders can be reduced to the number of tap coefficients to be set, and the circuit scale can be significantly reduced.

[Embodiment 3] FIG. 11 is a block diagram of a ghost removing apparatus according to a third embodiment of the present invention. The ghost removing device is supplied with an input signal x and a filter circuit 31 that outputs an output signal y, an error signal generator 32 to which an output signal y from the filter circuit 31 is input, and the error signal generator 32. A reference signal generator 33 for generating a reference signal r, a correlation calculator 34 to which the error signal e from the error signal generator 32 and the reference signal r from the reference signal generator 33 are supplied, and a correlation calculator 34 from the correlation calculator 34. It comprises a maximum / maximum detection unit 35 to which a signal is supplied and a tap coefficient calculation unit 36 to which the output from the maximum / maximum detection unit 35 is input.

In the above structure, first, the input signal x is input to the filter circuit 31 and the output signal y is output.
Next, the error signal generator 32 subtracts the reference signal r generated by the reference signal generator 33 from the output signal y of the filter circuit 31 to generate the error signal e. next,
In the correlation calculator 34, the correlation s between the reference signal r, which is the first signal for comparison, and the error signal e, which is the second signal including the ghost signal, is obtained. When the number of taps corresponding to the width of the reference signal r is M, the correlation s is given by the equation (7).

[0078]

[Equation 7]

Next, the maximum / maximum detection unit 35 detects the position where the absolute value of the correlation s has the maximum value or the maximum value, and the tap coefficient calculation unit 36 determines the tap coefficient c corresponding to the detected position. Ask. The filter circuit 11 is I
In the case of the IR type configuration, if the tap coefficient c _i is set to a value obtained by dividing the value of the correlation s by the square integral value of the reference signal r that is the first signal for comparison as shown in Expression (8), The number of corrections of the tap coefficient c _i at this position is only once. When a FIR type filter circuit is used, it is dealt with by converting the tap coefficient.

[0080]

[Equation 8]

This is sent to the filter circuit 31 to correct the tap coefficient. The output signal y is calculated again, and the above correction process is repeated until the evaluation function E becomes small to some extent. The final tap coefficient is obtained by repeating the correction of the tap coefficient several times.

FIG. 12 shows the signal waveform in the above processing steps, and the output signal y from which the ghost signal is removed from the input signal x is obtained.

In the second embodiment, the input signal x is used as the first signal for comparison, and N / 2 times of product-sum calculation processing on average are required to obtain one correlation value. However, here, by using the reference signal r, equation (7)
As shown in, the calculation of one correlation value requires M times of product-sum calculation processing. The number M of taps corresponding to the width of the reference signal generally used is the number N of taps of the transversal filter.
Since it is small, that is, a fraction of a few to a few tens of minutes, the calculation amount is reduced.

[Fourth Embodiment] FIG. 13 is a block diagram of a ghost removing apparatus according to a fourth embodiment of the present invention. The ghost removing device is supplied with an input signal x and a filter circuit 41 that outputs an output signal y, an intermediate signal generator 47 to which the input signal x from the filter circuit 41 is input, and the intermediate signal generator 47. A reference signal generating section 43 for generating a reference signal r, a correlation calculating section 44 to which the intermediate signal x ′ from the intermediate signal generating section 47 and the reference signal r from the reference signal generating section 43 are supplied, and the correlation calculating section 44. Maximum / maximum detection section 45 to which the signal of
It is composed of a tap coefficient calculator 46 to which the output from is input. The output from the tap coefficient calculator 46 is supplied to the filter circuit 41 and also to the intermediate signal generator 47.

In the above structure, first, the intermediate signal generator 47 subtracts the reference signal r generated by the reference signal generator 43 from the input signal x to generate the intermediate signal x '. Next, the correlation calculation unit 44 obtains the correlation s between the reference signal r, which is the first signal for comparison, and the intermediate signal x ′, which is the second signal including the ghost signal. If the number of taps corresponding to the width of the reference signal r is M, the correlation s
Is given by equation (9).

[0086]

[Equation 9]

Next, in the maximum / maximum detector 45, the correlation s
The position where the absolute value of is the maximum value or the maximum value is detected, and the tap coefficient calculation unit 46 obtains the tap coefficient c corresponding to the detected position. Similar to the second embodiment, the tap coefficient c _i is calculated by the equation (8).

This is sent to the filter circuit 41 to correct the tap coefficient. At the same time, in the intermediate signal generator 47, only the area of the intermediate signal x ′ that changes with the modified tap coefficient is updated, and the above-described modification processing is repeated until the evaluation function E becomes small to some extent. The final tap coefficient is obtained by repeating the correction of the tap coefficient several times.

FIG. 14 shows a signal waveform in the above process, and an output signal y in which a ghost signal is removed from an input signal x is obtained.

Since the error signal e is used as the second signal including the ghost in the third embodiment, the tap coefficient is corrected, and then the next correction is performed again based on the output from the filter circuit. Every time the correction is performed, the calculation in the filter circuit has to be performed, and many calculations are required. Here, the intermediate signal is used as the second signal including the ghost, and only the limited region related to the corrected tap coefficient of the intermediate signal needs to be updated, and the intermediate signal can be generated faster than the error signal e. Therefore, the tap coefficient can be obtained at high speed.

[Embodiment 5] FIG. 16 is a block diagram of a ghost removing apparatus according to a fifth embodiment of the present invention. The ghost removing device is supplied with an input signal x and a filter circuit 51 that outputs an output signal y, an intermediate signal generator 57 to which the input signal x from the filter circuit 51 is input, and the intermediate signal generator 57. A reference signal generator 53 for generating a reference signal r, an intermediate signal x ′ from the intermediate signal generator 57, and a correlation calculator 54 to which the reference signal r from the reference signal generator 53 is supplied. Of the correlation selection unit 58, the maximum / maximum detection unit 55 to which the signal from the correlation selection unit 58 is supplied, and the tap coefficient calculation unit 56 to which the output from the maximum / maximum detection unit 55 is input. Composed of. The output from the tap coefficient calculator 56 is supplied to the filter circuit 51 and also to the intermediate signal generator 57.

In the above structure, first, the intermediate signal generator 57 generates the intermediate signal x'by subtracting the reference signal r generated by the reference signal generator 53 from the input signal x. Next, in the correlation calculation unit 54, the reference signal r
Correlation s1 between the rising edge of the pulse and the intermediate signal z
And the correlation s2 between the trailing edge of the pulse of the reference signal r and the intermediate signal z. Correlations s1 and s2 are L, the number of taps corresponding to the rising and falling portions of the pulse of the reference signal r, N, the number of taps corresponding to the ghost removal region, and the tap corresponding to the pulse width of the reference signal r. When the number is J, it is given by the equation (10) and the equation (11). Here, r1 and r2 are average values of the rising portion and the falling portion of the pulse of the reference signal r, respectively, and are represented by the equations (12) and (13).

[0093]

[Equation 10]

[0094]

[Equation 11]

[0095]

[Equation 12]

[0096]

[Equation 13]

Next, in the correlation selection unit 58, the correlation s1
And s2, the smaller absolute value is selected to obtain the correlation s, the maximum / maximum detection unit 55 detects the position where the absolute value of the correlation s has the maximum value or the maximum value, and the tap coefficient calculation unit 56 A tap coefficient c corresponding to the detected position is obtained. When the filter circuit 51 has an IIR type configuration, the tap coefficient c is obtained by the equation (14). When the filter circuit 11 has the FIR type configuration, the equation (14) is used.
It can be dealt with by converting the tap coefficient obtained in.

[0098]

[Equation 14]

The tap coefficient c calculated by the tap coefficient calculation unit 56 is sent to the filter circuit 51, and at the same time, the intermediate signal generation unit 5
In step 7, the intermediate signal x ′ is obtained by updating only the area changed by the corrected tap coefficient c. Further, the correlation s with respect to the intermediate signal x'is obtained, and the tap coefficient c corrected by this is obtained.

The ghost elimination result is evaluated by the evaluation function E shown in the equation (15). When the above correction process is repeated until the evaluation function E becomes small to some extent, the intermediate signal x'is almost zero.
Finally, the output signal y is obtained by removing the ghost signal from the input signal x.

[0101]

[Equation 15]

FIG. 17 shows the signal waveform in the above processing steps, and the output signal y from which the ghost signal is removed from the input signal x is obtained.

In the fourth embodiment, as shown in FIG. 15, in the correlation s with respect to the ghost signal, sub-peaks having opposite signs to the central peak and having a magnitude of about ½ appear on both sides of the central peak. If there are multiple ghost signals, the correlation will be the sum of the correlations for each ghost signal,
Depending on the position and size of the ghost, the sum of the sub-peaks may have a larger absolute value than the original center peak, and the tap coefficient corresponding to this position will be corrected. As a result, a false ghost signal is added to the position of the intermediate signal x'where no ghost signal exists, and normal ghost removal cannot be performed. Further, as shown in FIG. 15, a large correlation with noise also appears. Therefore, the noise component may be regarded as a ghost and the tap coefficient corresponding to the position of the noise may be corrected. As a result,
As a result, a false ghost signal is added to the position of the intermediate signal z where the ghost signal does not exist, and normal ghost removal cannot be performed. Further, as shown in FIG. 15, since the shape of the peak of the correlation s is gentle, when the deviation between the position of the maximum value or the maximum value of the absolute value of the correlation and the position of the original ghost signal becomes large. There is.

Due to the above problems, according to the fourth embodiment, the efficiency of ghost removal is lowered and the number of corrections of the tap coefficient until the ghost signal is sufficiently removed increases. However, according to the present embodiment, the false ghost signal is removed. The tap coefficient can be obtained at high speed without adding the following. The correlation used in the present embodiment will be described in detail below with reference to FIG. Correlations between the rising portion (the number of taps L) and the trailing portion (the number of taps L) of the reference signal r and the intermediate signal z have shapes like s1 and s2, respectively. Here, the correlation s1
The left and right positions of s2 and s2 are set to be displaced by the number of taps J corresponding to the pulse width of the reference signal r. In the correlations s1 and s2, there are two peaks corresponding to the rising edge and the falling edge of the pulse of the ghost signal, respectively. Peaks are canceled out and sub-peaks do not occur, resulting in one peak.
Further, in the correlations s1 and s2, there are peaks corresponding to noise, but they are apart from each other by the number of taps J and are canceled in the correlation s. When there are a plurality of noises, the smaller value of the noise component is selected from the correlations s1 and s2, so that the noise component included in the correlation s becomes smaller. Further, in the correlation s, the width of the peak with respect to the ghost signal corresponds to the tap number L (<M),
The shape of the peak becomes steeper than the correlation s shown in FIG.

[Embodiment 6] A ghost removing apparatus according to a sixth embodiment of the present invention is different from the fifth embodiment in that the method of obtaining the correlation is changed. That is, in the correlation calculation unit 54 of FIG. 16, together with the correlations s1 and s2, the correlation s0 between the entire pulse of the reference signal r and the intermediate signal x ′ is obtained by the equations (16) and (17), and the correlation selection unit 58
In, the value having the smaller absolute value is selected from the correlations s0, s1, and s2 to be the correlation s.

[0106]

[Equation 16]

[0107]

[Equation 17]

Here, the correlation s0 is the same as the correlation s shown in FIG. Next, similarly to the fifth embodiment, the tap coefficient c is calculated and the intermediate signal x ′ is updated repeatedly, and finally the output signal y in which the ghost signal is removed from the input signal x is obtained. The signal waveform in the processing process is the same as in the case of the fifth embodiment shown in FIG. In this embodiment, the correlation s
Since a value having a smaller absolute value is selected from 0, s1, and s2 as the correlation s, the degree of canceling the noise component becomes stronger than that in the fifth embodiment, and the noise component that remains without being canceled in the fifth embodiment is also small. Become.

FIG. 19 shows a fourth embodiment, a fifth embodiment,
It is a figure which shows an example of the correction process of the tap coefficient with respect to the actual signal in each ghost removal apparatus of a 6th Example. In the figure, the solid line is according to the fourth embodiment, the broken line is according to the fifth embodiment, and the alternate long and short dash line is according to the sixth embodiment. In the fifth embodiment as compared with the fourth embodiment,
The evaluation function E becomes smaller with a smaller number of modifications, and
Since the evaluation function E at the time of saturation is also small, the efficiency of ghost removal is high and the tap coefficient can be obtained at high speed. Further, in the sixth embodiment, the efficiency of ghost removal is improved as compared with the fifth embodiment.

In the above embodiment, the reference signal r
Although the number of taps corresponding to the rising and falling portions of the pulse is the same, the number of taps may be different.

Further, in the above-mentioned embodiment, each processing is divided into corresponding processing units, but the method of construction does not depend on the above-mentioned embodiment, and it may be processed in one arithmetic unit and can be programmed by a general-purpose CPU. Processing may be performed.

Further, equations (5), (7), (9), (10) (1)
1) Although the correlation is obtained as in (16), the influence of direct current displacement may be prevented by obtaining the correlation between the signals obtained by subtracting the average of the respective signals.

[0113]

All of the ghost removing devices according to the present invention are provided with the reference signal generating means for outputting the equalization pulse within the vertical blanking period as the reference signal. In addition, ten signals can be used per field, and as a result, the signal acquisition time can be significantly shortened. Therefore, it becomes possible to shorten the ghost removal time, and it becomes possible to support a vehicle-mounted or portable television.

Further, in the ghost eliminating device according to the fourth aspect, the reference signal generating means comprises a storage means for storing in advance a standard signal waveform of the equalized pulse, and the reference signal generating means is stored in the storage means. Since the standard signal waveform of the stored equalization pulse is output as the reference signal, in addition to the above, it is possible to remove even a proximity ghost overlapping the equalization pulse.

Further, in the ghost removing apparatus according to the fifth aspect, the reference signal generating means includes means for cutting out an equalizing pulse from the input signal, and the reference signal generating means is a reference for the signal waveform cut out from the input signal. Since the signal is output as a signal, in addition to the above, the ghost can be removed even when the equalized pulse of the input signal deviates from its typical waveform.

Further, the ghost elimination device according to the sixth aspect is a means for obtaining a correlation between a first signal for comparison and a second signal including a ghost signal, and a maximum absolute value of the correlation or And a means for correcting the tap coefficient of the filter circuit corresponding to the position of the maximum value, so that only the tap coefficient corresponding to the position where the ghost exists is corrected and the error is sufficiently reduced. It is possible to reduce the number of corrections of the tap coefficient and to set the tap coefficient only at the position where the ghost exists. Therefore, the number of tap coefficient memory, multiplier and adder can be significantly reduced, and the circuit scale can be reduced. Can be significantly reduced.

Further, in the ghost eliminating device according to the seventh aspect, in the means for correcting the tap coefficient, a value obtained by dividing the correlation by the square integral value of the first signal is used as the correction value of the tap coefficient. Therefore, the number of corrections for one tap coefficient may be one, and the number of corrections until the error becomes sufficiently small can be reduced.

Further, the ghost removing device according to the eighth aspect is characterized in that the reference signal is used as the first signal, so that the integration area in the correlation calculation is limited to the width of the reference signal, The amount of calculation is reduced, and the tap coefficient can be obtained at high speed.

Further, the ghost removing apparatus according to claim 9 uses the intermediate signal obtained by subtracting the reference signal from the input signal as the second signal, and updates the intermediate signal in response to the correction of the tap coefficient. Since this is a feature, it is only necessary to update a limited area of the modified tap coefficient of the intermediate signal, and the tap coefficient can be obtained at high speed.

Further, in the ghost eliminating device according to the tenth aspect, the means for obtaining the correlation has a means for obtaining a first correlation between the rising portion of the pulse of the first signal and the second signal. Means for obtaining a second correlation between the trailing edge of the pulse of the first signal and the second signal; and means for selecting a value having a smaller absolute value from these correlations to obtain the third correlation. Since it is provided, it is possible to cancel one of the two peaks in each of the first correlation and the second correlation, and in the third correlation, no sub-peak occurs and the peak becomes one. Therefore, the false ghost is not added to the position where the ghost signal of the intermediate signal does not exist due to the influence of the sub-peak, and the normal ghost can be removed. Further, the noise component included in the first correlation and the second correlation is canceled, and the noise component included in the third correlation is reduced. Therefore, the false ghost is not added to the position where the ghost signal of the intermediate signal does not exist due to the influence of noise, and the normal ghost can be removed. Further, since the correlation is obtained in the areas of the rising and falling portions of the pulse of the reference signal, the shape of the correlation peak becomes steep. Therefore, the deviation generated between the position of the maximum value or the maximum value of the absolute value of the correlation and the original position of the ghost signal becomes small. From the above, the efficiency of ghost removal is improved, and the number of tap coefficient modifications required to sufficiently remove the ghost signal is reduced.

Further, in the invention according to claim 11, the means for obtaining the correlation includes a means for obtaining a first correlation between the rising portion of the pulse of the first signal and the second signal, and a first means. Means for determining a second correlation between the falling edge of the pulse of the signal and the second signal, and means for determining a third correlation between the entire pulse of the first signal and the second signal, Since there is provided means for selecting a value having a smaller absolute value from among the corresponding first correlation, second correlation and third correlation to obtain the fourth correlation, the degree of canceling the noise component is further increased. The noise component included in the fourth correlation becomes stronger and becomes smaller.
Therefore, the efficiency of ghost removal is further improved, and the number of tap coefficient modifications required to sufficiently remove the ghost signal is reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a ghost removing device of the present invention.

FIG. 2 is a diagram showing an equalizing pulse (arrow portion) used as a reference signal in the first embodiment of the ghost eliminating device according to the present invention.

FIG. 3 is a simulation result of ghost elimination when only a portion corresponding to rising / falling portions of an equalization pulse is cut out from an input signal and used as a reference signal by the first embodiment of the ghost eliminating apparatus according to the present invention. It is the figure which showed.

FIG. 4 is a simulation result of ghost removal when only a portion corresponding to rising / falling portions of an equalization pulse is cut out from an input signal and used as a reference signal by the first embodiment of the ghost removing apparatus according to the present invention. It is the figure which showed.

FIG. 5 shows a ghost elimination simulation result when a portion corresponding to a rising edge / falling edge of a standard equalization pulse from a ROM is used as a reference signal by the first embodiment of the ghost elimination device according to the present invention. It is a figure.

FIG. 6 is a simulation result of ghost elimination when only a portion corresponding to rising / falling portions of an equalization pulse is cut out from an input signal and used as a reference signal by the first embodiment of the ghost eliminating apparatus according to the present invention. It is the figure which showed.

FIG. 7 is a diagram showing a ghost elimination simulation result when the entire equalized pulse is cut out from an input signal and used as a reference signal by the first embodiment of the ghost elimination apparatus according to the present invention. It is the figure which showed the simulation result when removing a ghost.

FIG. 8 is a block diagram showing a second embodiment of the ghost removing device according to the present invention.

FIG. 9 is a signal waveform diagram showing the processing steps of the second embodiment of the ghost eliminating device according to the present invention.

FIG. 10 is a diagram showing a configuration of a transversal filter used in the ghost removing device according to the present invention.

FIG. 11 is a block diagram showing a third embodiment of the ghost removing device according to the present invention.

FIG. 12 is a signal waveform diagram showing the processing steps of the third embodiment of the ghost eliminating device according to the present invention.

FIG. 13 is a block diagram showing a fourth embodiment of the ghost removing device according to the present invention.

FIG. 14 is a signal waveform diagram showing the processing steps of a fourth embodiment of the ghost removing device according to the present invention.

FIG. 15 is a diagram for explaining the correlation in the fourth embodiment of the ghost removing device according to the present invention.

FIG. 16 is a block diagram showing a fifth embodiment of the ghost removing device according to the present invention.

FIG. 17 is a diagram showing a signal waveform in the processing process of the fifth embodiment of the ghost removing device according to the present invention.

FIG. 18 is an explanatory diagram of a correlation in the fifth embodiment of the ghost removing device according to the present invention.

FIG. 19 is a diagram showing an example of a tap coefficient correction process according to fourth, fifth and sixth embodiments of the ghost removing device according to the present invention.

FIG. 20 is a diagram showing a configuration of an FIR type filter circuit using a transversal filter.

FIG. 21 is a diagram showing a configuration of an IIR type filter circuit using a transversal filter.

FIG. 22 is a diagram showing a configuration of a filter circuit using both FIR type and IIR type using a transversal filter.

FIG. 23 is a diagram showing a configuration of a transversal filter used in a conventional ghost removing device.

FIG. 24 is a block diagram showing a ghost removing device using a conventional iterative correction method.

FIG. 25 is a signal waveform diagram showing a processing process of a ghost removing apparatus using a conventional iterative correction method.

[Simple explanation of symbols]

11, 21, 31, 41, 51, 61 Filter circuit 12, 22, 32, 42, 52, 62 Error signal generation unit 13, 23, 33, 43, 53, 63 Reference signal generation unit 14, 24, 34, 44 , 54, 64 Correlation calculation section 25, 35, 45, 55 Maximum / maximum detection section 16, 26, 36, 46, 56, 66 Tap coefficient calculation section 47, 57 Intermediate signal generation section 58 Correlation selection section

Claims (11)

[Claims] 1. A ghost elimination device for processing an input signal by a filter circuit and outputting a signal from which a ghost signal has been eliminated, wherein the ghost elimination device is the first of 12 equalized pulses in a vertical blanking period. And a reference signal generating means for outputting 10 pulses other than the seventh pulse as a reference signal, a means for obtaining a correlation between the reference signal and a signal including a ghost signal, and a tap coefficient of the filter circuit is corrected based on the correlation. Means for removing ghosts. 2. A ghost removing device for processing an input signal by a filter circuit and outputting a signal from which a ghost signal has been removed, wherein a reference signal generating device outputs an equalized pulse within a vertical blanking period as a reference signal. Means, means for obtaining a correlation between a reference signal and a signal including a ghost signal at rising and falling portions of the equalized pulse, and means for correcting the tap coefficient of the filter circuit based on the correlation. A ghost removal device. 3. A ghost removing device for processing an input signal by a filter circuit and outputting a signal from which a ghost signal has been removed, wherein a reference signal generating device outputs an equalization pulse within a vertical blanking period as a reference signal. Means, means for obtaining the correlation between the reference signal and a signal containing the ghost signal for the entire equalized pulse, and means for correcting the tap coefficient of the filter circuit based on the correlation. Removal device. 4. The standard signal of the equalizing pulse, wherein the reference signal generating means comprises a storage means for storing a standard signal waveform of the equalizing pulse in advance, and the reference signal generating means is stored in the storage means. The ghost elimination device according to any one of claims 1 to 3, wherein a waveform is output as a reference signal. 5. The reference signal generating means comprises means for cutting out an equalized pulse from an input signal, and the signal waveform cut out by the reference signal generating means is output as a reference signal. The ghost removing device according to any one of 1. 6. A ghost elimination device for processing an input signal by a filter circuit and outputting a signal from which a ghost signal has been eliminated, wherein a first signal for comparison and a second signal containing the ghost signal are compared. A ghost eliminating device comprising: means for obtaining a correlation; and means for correcting a tap coefficient of the filter circuit corresponding to a position of a maximum value or a maximum value of the absolute value of the correlation. 7. The means for modifying the tap coefficient is configured to use a value obtained by dividing the correlation by a square integral value of the first signal as a modification value of the tap coefficient. Item 5. The ghost removing device according to item 6. 8. The ghost elimination device according to claim 6, wherein a reference signal is used as the first signal. 9. A means for generating an intermediate signal by subtracting a reference signal from an input signal and further updating the intermediate signal in response to correction of a tap coefficient, wherein the means for obtaining the correlation outputs the intermediate signal. The ghost elimination device according to claim 8, wherein the ghost elimination device is configured to be used as the second signal. 10. The means for obtaining the correlation includes means for obtaining a first correlation between the rising edge of the pulse of the first signal and the second signal, and the falling edge of the pulse of the first signal. Means for obtaining a second correlation with the second signal, and means for selecting a value having a smaller absolute value from the corresponding first correlation and second correlation to obtain the third correlation. The means for modifying the tap coefficient is configured to modify the tap coefficient of the filter circuit corresponding to the position of the maximum value or the maximum value of the absolute value of the third correlation. The ghost removing device according to claim 9. 11. The means for obtaining the correlation includes a means for obtaining a first correlation between the rising edge of the pulse of the first signal and the second signal, and a falling edge of the pulse of the first signal. Means for determining a second correlation with the second signal, means for determining a third correlation between the entire pulse of the first signal and the second signal, and the corresponding first correlation and A value having a smaller absolute value is selected from the second correlation and the third correlation to select the fourth correlation.
And means for correcting the tap coefficient, wherein the means for correcting the tap coefficient corrects the tap coefficient of the filter circuit corresponding to the position of the maximum value or the maximum value of the absolute value of the fourth correlation. It is constituted, It is characterized by the above-mentioned.
The described ghost removing device.